MC Test Environment Won't Start, No Matter What I Try.

yep, i know what you mean, but it keeps coming up with errors for nonexistent items.

Executing gradle command: runClient
Build info: MCreator 1.8.3, 64-bit, 8056 MB, Windows 10 - cmd, JVM 1.8.0_202, JAVA_HOME: C:\Users\TRACEY~1\AppData\Local\Temp\Rar$EXa0.184\MCreator1.8.3[1.12.2]Windows64bit\jdk
C:\Users\TRACEY~1\AppData\Local\Temp\Rar$EXa0.184\MCreator1.8.3[1.12.2]Windows64bit\forge>gradlew -Dorg.gradle.java.home="C:/Users/TRACEY~1/AppData/Local/Temp/Rar$EXa0.184/MCreator1.8.3[1.12.2]Windows64bit/jdk" -Dorg.gradle.parallel=false -Dorg.gradle.jvmargs="-Xms756m -Xmx2048m" runClient 
Starting a Gradle Daemon, 12 incompatible Daemons could not be reused, use --status for details
This mapping 'snapshot_20171003' was designed for MC 1.12! Use at your own peril.
#################################################
         ForgeGradle 2.3-SNAPSHOT-7764e3e        
  https://github.com/MinecraftForge/ForgeGradle  
#################################################
                 Powered by MCP                  
             http://modcoderpack.com             
     by: Searge, ProfMobius, R4wk, ZeuX          
     Fesh0r, IngisKahn, bspkrs, LexManos         
#################################################
:deobfCompileDummyTask
:deobfProvidedDummyTask
:sourceApiJava
:compileApiJava NO-SOURCE
:processApiResources NO-SOURCE
:apiClasses UP-TO-DATE
:sourceMainJava
C:\Users\Tracey Johnson\AppData\Local\Temp\Rar$EXa0.184\MCreator1.8.3[1.12.2]Windows64bit\forge\build\sources\main\java\mod\mcreator\more_items.java:321: error: cannot find symbol
      elements.add(new mcreator_sffsBulletHitsBlock(this));
                       ^
  symbol:   class mcreator_sffsBulletHitsBlock
  location: class more_items
C:\Users\Tracey Johnson\AppData\Local\Temp\Rar$EXa0.184\MCreator1.8.3[1.12.2]Windows64bit\forge\build\sources\main\java\mod\mcreator\more_items.java:322: error: cannot find symbol
      elements.add(new mcreator_sffsBulletHitsLivingEntity(this));
                       ^
  symbol:   class mcreator_sffsBulletHitsLivingEntity
  location: class more_items
C:\Users\Tracey Johnson\AppData\Local\Temp\Rar$EXa0.184\MCreator1.8.3[1.12.2]Windows64bit\forge\build\sources\main\java\mod\mcreator\more_items.java:323: error: cannot find symbol
      elements.add(new mcreator_sffs(this));
                       ^
  symbol:   class mcreator_sffs
  location: class more_items
C:\Users\Tracey Johnson\AppData\Local\Temp\Rar$EXa0.184\MCreator1.8.3[1.12.2]Windows64bit\forge\build\sources\main\java\mod\mcreator\more_items.java:324: error: cannot find symbol
      elements.add(new mcreator_weatherdialRightClickedOnBlock(this));
                       ^
  symbol:   class mcreator_weatherdialRightClickedOnBlock
  location: class more_items
C:\Users\Tracey Johnson\AppData\Local\Temp\Rar$EXa0.184\MCreator1.8.3[1.12.2]Windows64bit\forge\build\sources\main\java\mod\mcreator\more_items.java:325: error: cannot find symbol
      elements.add(new mcreator_weatherdial(this));
                       ^
  symbol:   class mcreator_weatherdial
  location: class more_items
C:\Users\TraceyJohnson\AppData\Local\Temp\Rar$EXa0.184\MCreator1.8.3[1.12.2]Windows64bit\forge\build\sources\main\java\mod\mcreator\more_items.java:326: error: cannot find symbol
      elements.add(new mcreator_daymoonRightClickedInAir(this));
                       ^
  symbol:   class mcreator_daymoonRightClickedInAir
  location: class more_items
C:\Users\Tracey Johnson\AppData\Local\Temp\Rar$EXa0.184\MCreator1.8.3[1.12.2]Windows64bit\forge\build\sources\main\java\mod\mcreator\more_items.java:327: error: cannot find symbol
      elements.add(new mcreator_daymoon(this));
                       ^
  symbol:   class mcreator_daymoon
  location: class more_items
C:\Users\Tracey Johnson\AppData\Local\Temp\Rar$EXa0.184\MCreator1.8.3[1.12.2]Windows64bit\forge\build\sources\main\java\mod\mcreator\more_items.java:328: error: cannot find symbol
      elements.add(new mcreator_dustrock(this));
                       ^
  symbol:   class mcreator_dustrock
  location: class more_items
C:\Users\Tracey Johnson\AppData\Local\Temp\Rar$EXa0.184\MCreator1.8.3[1.12.2]Windows64bit\forge\build\sources\main\java\mod\mcreator\more_items.java:329: error: cannot find symbol
      elements.add(new mcreator_slush(this));
                       ^
  symbol:   class mcreator_slush
  location: class more_items
C:\Users\Tracey Johnson\AppData\Local\Temp\Rar$EXa0.184\MCreator1.8.3[1.12.2]Windows64bit\forge\build\sources\main\java\mod\mcreator\more_items.java:330: error: cannot find symbol
      elements.add(new mcreator_dust(this));
                       ^
  symbol:   class mcreator_dust
  location: class more_items
C:\Users\Tracey Johnson\AppData\Local\Temp\Rar$EXa0.184\MCreator1.8.3[1.12.2]Windows64bit\forge\build\sources\main\java\mod\mcreator\more_items.java:331: error: cannot find symbol
      elements.add(new mcreator_manowarMobIsHurt(this));
                       ^
  symbol:   class mcreator_manowarMobIsHurt
  location: class more_items
C:\Users\Tracey Johnson\AppData\Local\Temp\Rar$EXa0.184\MCreator1.8.3[1.12.2]Windows64bit\forge\build\sources\main\java\mod\mcreator\more_items.java:332: error: cannot find symbol
      elements.add(new mcreator_manowar(this));
                       ^
  symbol:   class mcreator_manowar
  location: class more_items
C:\Users\Tracey Johnson\AppData\Local\Temp\Rar$EXa0.184\MCreator1.8.3[1.12.2]Windows64bit\forge\build\sources\main\java\mod\mcreator\mcreator_fd.java:70: error: incompatible types: Entityfd cannot be converted to EntityCreature
         this.tasks.addTask(1, new EntityAIWander(this, 1));
                                                  ^
C:\Users\Tracey Johnson\AppData\Local\Temp\Rar$EXa0.184\MCreator1.8.3[1.12.2]Windows64bit\forge\build\sources\main\java\mod\mcreator\mcreator_fd.java:74: error: incompatible types: Entityfd cannot be converted to EntityCreature
         this.tasks.addTask(5, new EntityAIPanic(this, 1.2));
                                                 ^
C:\Users\Tracey Johnson\AppData\Local\Temp\Rar$EXa0.184\MCreator1.8.3[1.12.2]Windows64bit\forge\build\sources\main\java\mod\mcreator\mcreator_fd.java:75: error: incompatible types: Entityfd cannot be converted to EntityCreature
         this.targetTasks.addTask(6, new EntityAIHurtByTarget(this, false));
                                                              ^
Note: Some messages have been simplified; recompile with -Xdiags:verbose to get full output
15 errors
:compileJava FAILED
FAILURE: Build failed with an exception.
* What went wrong:
Execution failed for task ':compileJava'.
> Compilation failed; see the compiler error output for details.
* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.
* Get more help at https://help.gradle.org
BUILD FAILED in 30s
5 actionable tasks: 5 executed
C:\Users\TRACEY~1\AppData\Local\Temp\Rar$EXa0.184\MCreator1.8.3[1.12.2]Windows64bit\forge>
Task completed with return code 0 in 30914 milliseconds

What In The Name Of Lord Neptune Does Any Of This Mean?!

OH MY GOD THANKS 😊👍👌